The proposed project aims to facilitate the use of flexible laparoscopic ultrasound transducers during minimally invasive surgery (MIS) in order to reduce injury rates. During a standard laparoscopic procedure, the surgeon operates through small incisions in the abdomen while viewing the internal anatomy on a remote video monitor, creating an eye-hand-instrument spatial coordination problem. Because of this, many injuries occur during MIS procedures. Laparoscopic ultrasound provides a more thorough understanding of the anatomy, offering complementary anatomical information to the laparoscopic camera image and thereby decreasing the risk of injury. However, its use aggravates the inherent spatial coordination problem of conventional MIS, since the same anatomical features appear very differently between the two imaging modalities. Precisely placing interventional instruments such as needles becomes particularly difficult without extensive experience.This problem is addressed with the guidance system of this project, which shows the surgeon how his instruments are positioned with respect to features in the ultrasound scan. The dynamic stereoscopic imagery of the Phase I system shows the current position and orientation of the needle as well as its future trajectory, integrated with the live ultrasound image. Both needle and ultrasound scan are presented to the user in their actual spatial orientations. In Phase I, a prototype system was developed and its efficacy tested. The results were stunning: two expert users increased their placement accuracy from 60% without our guidance to 100% with it;while two novice users (who had never before held an ultrasound probe) improved from 5% accuracy without our guidance to 100% with it. In other words, the novice users were not able to place the needle into a feature in the LUT video without our system, and with it they could not miss. In this Phase II project, we propose to (1) investigate new capabilities that will increase the usefulness of the system;and (2) to continue refinement of the prototype so that, at the project's conclusion, it will be ready for clinical trials with human subjects. It will be tested both quantitatively and qualitatively in multiple animal studies. We will also test its usability in a clinical setting, as well as experimentally evaluate the usefulness of the novel features developed throughout Phase II. PUBLIC HEALTH RELEVANCE: We propose to develop an advanced stereoscopic visualization system for minimally-invasive surgery that facilitates the use of laparoscopic ultrasound during MIS interventions, in order to reduce patient injury rates. The system offers three-dimensional guidance for accurate placement of needles or other interventional instruments into structures seen in the laparoscopic ultrasound image, so that the surgeon can conduct the procedure more easily and more safely.